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/***
*87except.c - floating point exception handling
*
* Copyright (c) 1991-1991, Microsoft Corporation. All rights reserved.
*
*Purpose:
*
*Revision History:
* 8-24-91 GDP written
* 9-26-91 GDP changed DOMAIN error handling
* 1-29-91 GDP renamed to 87exept.c
* 3-15-92 GDP support raising exceptions
*
*******************************************************************************/
#include <errno.h>
#include <math.h>
#include <trans.h>
#define _DOMAIN_QNAN 7 /* should be in sync with elem87.inc */
#define _INEXACT 8 /* should be in sync with elem87.inc */
int _matherr_flag;
extern void _raise_exc(_FPIEEE_RECORD *prec,unsigned int *pcw,
int flags, int opcode, double *parg1, double *presult);
extern void _set_errno(int matherrtype);
extern int _handle_exc(unsigned int flags, double * presult, unsigned int cw);
/***
*double _87except(struct _exception *except, unsigned int *cw)
*
*Purpose:
* Handle floating point exceptions.
*
*Entry:
*
*Exit:
*
*Exceptions:
*******************************************************************************/
void _87except(int opcode, struct _exception *exc, unsigned short *pcw16)
{
int fixed;
unsigned int flags;
unsigned int cw, *pcw;
//
// convert fp control word into an unsigned int
//
cw = *pcw16;
pcw = &cw;
switch (exc->type) {
case _DOMAIN:
case _TLOSS:
flags = FP_I;
break;
case _OVERFLOW:
flags = FP_O | FP_P;
break;
case _UNDERFLOW:
flags = FP_U | FP_P;
break;
case _SING:
flags = FP_Z;
break;
case _INEXACT:
flags = FP_P;
break;
case _DOMAIN_QNAN:
exc->type = _DOMAIN;
// no break
default:
flags = 0;
}
if (flags && _handle_exc(flags, &exc->retval, *pcw) == 0) {
//
// trap should be taken
//
_FPIEEE_RECORD rec;
//
// fill in operand2 info. The rest of rec will be
// filled in by _raise_exc
//
switch (opcode) {
case OP_POW:
case OP_FMOD:
case OP_ATAN2:
rec.Operand2.OperandValid = 1;
rec.Operand2.Format = _FpFormatFp64;
rec.Operand2.Value.Fp64Value = exc->arg2;
break;
default:
rec.Operand2.OperandValid = 0;
}
_raise_exc(&rec,
pcw,
flags,
opcode,
&exc->arg1,
&exc->retval);
}
/* restore cw */
_rstorfp(*pcw);
fixed = 0;
if (exc->type != _INEXACT &&
! _matherr_flag) {
fixed = _matherr(exc);
}
if (!fixed) {
_set_errno(exc->type);
}
}
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